The purpose of this project is determination of the structure of the carbohydrate chain or chains of the intrinsic membrane glycoprotein of red blood cells known as "band 3." This protein of approximate molecular weight 90,000 Daltons, which is a major constituent of the red cell membrane, has about 10% carbohydrate by weight. The composition is rather unusual, being mainly galactose and glucosamine with lesser amounts of mannose. Although band 3 is implicated in the transport of anions through the red cell membrane, it is not known whether the carbohydrate chains play any role in this biological function. Our immediate objective is to determine the site or sites of glycosylation on the peptide by studying the carbohydrate structures of certain band 3 fragments which are produced by specific proteolytic cleavage of the protein as it is situated in the membrane. Our current goal is to determine whether the fragment which is most closely associated with the lipid bilayer, and is hence most resistant to proteolytic cleavage, has sites of glycosylation. The oligosaccharides will be isolated by the hydrazinolysis method. High pressure liquid chromatrography (HPLC) will be used to fractionate the oligomers. Structures will be determined by established methods such as methylation analysis, gc - mass spectrometry of permethylated oligosaccharides or proton NMR.